Broaching machine



' 8 H. c. NYE ,3

BROACHINGIMACHIYNE k I Filed Feb. 2:, 193a 2 Sheets-Sheet 1 mv sm'oa HUGH; c. NYE

ATTORNEY "Oct. 8,1940.

H. c. NYE

BROACHING MACHINE Filed Feb 23, 19:58 2 sheets-Sheet 2v .FIG. E2

EBB

INVENTOR HUGH c. NYE BYMiL/W k ATTORNEY Patented Oct. 8, 1940 UNITED STATES PATENT OFFICE BROACHING MACHINE Hugh 0. Nye, Detroit, Mich, assignor to Vickers Incorporated, Detroit, Mich a corporation of Michigan Application February 23, 1938, Serial No. 192,027 14 Claims, (Cl. 90,-2.3)

predetermined sequence and may be used for example on a hydraulically operated breaching machine. In the art of surface breaching it is common to utilize a pair of oppositely moving breaching tools or rams, one of which performs a breaching stroke while the other simultaneously returns to starting position. Machines of this character are frequently provided with automatic loading fixtures which position a working piece in front of one tool and after the breachingstroke is completed shifts to remove that finished work piece and to place to new work piece in front of the other breaching tool, which, in the meantime, has returned to starting position. It is frequently desirable in certain types of breaching work to provide also automatic clamping means for positively holding the work piece in position during breaching.

It is an object ofthe present invention to provide a hydraulic power transmission system, par- 30 ticularly adapted for the automatic operation of a breaching machine of the character described with improved reliabili y, safety and economy of operation.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of the present invention is clearly shown.

In the drawings:

40 Figure 1 is a diagrammatic view showing a hydraulic circuit embodying a preferred form of the present invention.

Figure 2 is a top view of a breaching machine in which thetransmission system of the present invention may be incorporated.

Figure 3 is a front view of the breaching machine of Figure 2. v

An electric motor I8 is directly connected to operate three pumps, I2, I4 and I6. which have may be withdrawn from a tank 24. Pump I2 has a delivery conduit 26 in which is inserted a.

suction conduits I8, 26 and 22 through which oil whenever the control chamber 32 of the valve 28 is vented. The relief valve illustrated is similar to that shown in the Patent 2,043,453 to Harry F. Vickers. The conduit 26 connects to a pressure responsive, back pressure valve 34 adapted to open communication between a chamber 36 and a port 38 whenever apredetermined pressure is exceeded in the chamber 36.

Communicating with the port 38 is conduit 46, leading to the pressure port of a conventional servo-operated, closed center, four-way valve 42.

A conduit 44 connects the tank port of the valve 7 42 with the tank 24. The cylinder ports of the valve 42 connect by conduits 46 and 48, with the opposite ends of a cylinder 56. The latter has a piston 52 reciprocabl'y mounted therein and connected with a. rod 54 extending through both ends of the cylinder 56. The rod 54 may be operably connected to a suitable loading fixture for loading and unloading work pieces at the working stations in line with the breaching tools.

Pump I4 has a delivery conduit 56 in which is inserted a relief valve 58 having a control chamber 60 and of similar construction to the valve 28. The conduit 56 extends to the pressure port of a servo operated, four-way valve 62 which has its tank port connected by a conduit 64 with the tank 24. The cylinder ports -of the valve 62 are connected by conduits 66 and 68 with the head ends'of a pair of cylinders Ill and I2. Thelatter carry reciprocable pistons I4 and I6 having rods 18 and 88, to which suitable surface broaching tools may be attached. The rod ends of the cylinders III and 12 are connected together by a conduit 82. A branch conduit 84 extends to the discharge conduit 86 of the pump I6. A manual shut-off valve 88 is interposed in the conduit 84 while a relief valve 89 serves to relieve oil from: conduit to the tank if the pressure therein gets too high.

The discharge conduit 86 of the pump I6 has interposed therein a relief valve 81 which may be similar in construction to the back pressure valve 34 and which discharges oil to the tank through a conduit 90 whenever a predetermined pressure is exceeded in the conduit 86. The conduit 86 has two branches 92 and 94 which communicate with the pressure ports of a pair of spring biased servo-operated, four-way valves 96 and 98. Tank connections to these valves are estab lished by the conduits I00 and 102 while the cylinder ports are connected to opposite ends' are adapted to operate suitable clamping means associated with the loading mechanism.

In order to cause the various pistons 52, 14, 18, H8 and H8 to operate through a predetermined sequence of movements there are provided a series of pilot valves operated by the various pistons and which are connected by various pilot circuits to the operating chambers of the servo operated valves 42, 82, 98 and 98.

For the purpose of controlling operation of valve 42, a pilot valve I24 is provided, which is shown as a rotaryfour-way valve, having ports P, T, I and 2. The valve may be shifted between a position in which port P is connected to port I, and port T is connected to port 2 and a second position 45 away clockwise, in which port P is connected to port 2, and port T connected to port I. A conduit I28 connects from the delivery conduit 92 to the port P of valve I24. Port T is connected to tank by a conduit I28. Port I is connected by a conduit I38 to the left hand operating chamber of the valve 42 while port 2 is-connected by a conduit I32 to the right hand operating chamber of the valve 42.

The control chamber 32 of relief valve 28 is connected by a conduit I34 with a pilot valve close such communication.

The conduit I42 connects to the port P of a rotary pilot valve I44, similar in construction to the valve I24, and operable therewith through a common operating shaft. The port T connects by a conduit I48 with the tank. Port I connects by a conduit I48 with the port P of a. rotary pilot valve I58. Port T of valve I58 connects to a. conduit I52 while ports I and 2 connect by conduits I54 and I58 with the ports I and 2, respectively, of a rotary pilot valve I58. Port P of the latter is plugged while port T is connected to tank through a conduit I88.

The port 2 of valve I44 is connected by a conduit I82 to the port P of a rotary pilot valve I84. Port T of the latter connects by a conduit I88 with the tank while ports I and 2 are connected by conduits I88 and I18 with the ports I and 2 respectively of a rotary pilot valve I12. The port P of the latter is plugged while port T is connected by a conduit I14 to the tank.

A rotary pilot valve I 18 has its port P connected to the pressure conduit 92 by a conduit I18 and its port T connected to tank by a conduit I88. Parts I and 2 are connected by conduits I82 and I84 to the ports 2 and I, respectively. Of a rotary pilot valve I88. The latter is connected by a common operating shaft to the pilot valve I12 and has its port T plugged while its port P connects by a conduit I88 with the operating chamber of the valve 98.

A rotary pilot valve I98 has its port P connected to the conduit 92 by a conduit I92 and its port T to tank by a conduit I94. ,Ports I and 2 of the valve I98 connect by conduits I98 and I98 with the ports 2 and I, respectively, of a rotary pilot valve 288. The latter is connected by a common operating shaft to the pilot valve I58 and has its port T plugged and-its port P connected by a conduit 282 with the operating chamber of the valve 98. I

The control chamber 88 of the relief valve 58 is connected by a conduit 284 with a port 288 of a plunger type Pilot valve 288. A port 2I8 connects by a conduit 2I2 with a port 2| 4 of a plunger type pilot valve 2I8 identical to the valve 288. A port 2 I8 connects by a conduit 228 to tank. The valve 288 has a port 222 connected by a conduit 224 with the pressure conduit 92 and a port 228 connected by a conduit 228 with the right hand operating chamber of the valve 62. The valve 2I8 has a port 238 connected by a conduit 232 to the pressure conduit 92 and also has a port 234 connected by a conduit 238 with the left hand operating chamber of the valve 82. The valves 288 and 2I8 have tank ports 238' and 248 connected to tank by conduits 242 and 244.

A pair of rotary pilot valves 248 and 248 have their ports P and 2 plugged and their ports T connected to tank by a conduit 258. Port I of valve 248 connects 'by a conduit 252 to the conduit 284, leading from the control chamber of the relief valve 58. Valve 248 has its port I connected by a conduit 254 to the conduit I34 leading from the control chamber of the relief valve 28. I

The valves I58, I58, I84, I12, I18 and I88 each have a drain port D which is connected to tank for the purpose of draining leakage at the end chambers of the valve. Valves I24 and I44 are operated by a forked trip lever 258 which is actuated clockwise by a trip 258 on the stem 54 when the latter reaches the right hand limit of its movement. The lever 258 is operated counter clockwise by a trip 288 when the stem 54 reaches the left hand limit of its movement. Valve I18 is operated by a star wheel 282 clockwise A; of a revolution each time the rod 54 moves toward center position while traveling to the right. For thisv purpose a latch trip 284 is carried by the stem 54 which is ineffective on leftward movement of the stem 54. The valve I98 is operated by a star wheel 288 and is operated in an analogous manner in the opposite direction by a latch trip 288 also carried by the rod 54. The plungers of the valves 288 and 2I8 are adapted to be depressed by the rods I22 and I28 when the latter reach their fully projected position to the right and left respectively. When the plunger of valve 288 is up, as illustrated, port 288 is in communication with port 2I8 while port 222 is blocked and port 228 is connected to port 238. When the plunger is depressed ports 288 and 2I8 are blocked while port 228 is cut oil from port 238 and connected with port 222. Similar connections are established in the valve 2I8 when the same is operated by the rod I28.

Valves I58 and I84 are operated by star wheels 218 and 212 which in turn are actuated by latch trips 214 and 218 carried by the rods I28 and I22. The construction is such that star wheels are given of a revolution of movement of just prior to the time when the stem reaches its fully retracted position.

Valves I12 an :l I88 are operated by a star wheel 218 which in turn is actuated counter clockwise of a revolution by a latch trip 288 carried by the rod 88. The star wheel is actuated as the rod 88 reaches the lower limit of its movements.

Valves I58 and 288 are correspondently actuated 232 in which are mounted reciprocable slides 234- and 236; the latter are adapted to have suitable surface broachingtools such as indicated at 238 removably secured thereto. The slides 234 and 296 are fastened at their lower ends by backwardly extending brackets, not shown, to the piston rods I8 and 80 respectively. Theta-hie portion 286 carries a pair of horizontal'guideways 300 and 302 on which are reciprocably mounted a pair of work positioning slides 304 and 308, the latter having suitable recesses 308 and 3I0 in which the work piece, to be broached, may be positioned. The slides 304 and 306 are adapted to be alternately reciprocated inwardly and outwardly in the ,well known manner to position work pieces in. front of each broaching tool 298 at the start of the broaching stroke and remove the finished work at the completion thereof. A suitable hopper feed, not shown, may be provided for automatically loading the recesses 308 and 3I0 as they are retracted to their outer position. i

The piston rod 34 is arranged to actuate the slides 304 and 306 in the sequence required by any suitable mechanism. In the construction illustrated, the slides304 and 306 are provided with extension arms 3I'2 and 3I4 which lie in the path of collars 3I6 and 3"! rigidly secured to the rod 54. The extensions 3I2 and 3I4 are also connected by toggles 320 and 322 to stationary brackets 324 and 326 secured to the main frame.

The rod 54 carries a pair of cams 328 and 330. which are adapted to depress the center pivot of the toggle 322, for example, as the rod 54 moves to the right from itscentral position and thus break the toggle 322.

The rod 54 also carries a pair of cams 332 and 334 which are adaptedto lift the center pivot of the toggle 320, for example, as the rod 54 moves toward center position from its right hand position. Suitable compression springs 336 and, 338 yieldingly maintain the center pivot of the toggles in the path of movementof the cams 332 and 334. Suitable clamping means may be provided, comprising arms 340 and 342,-carried on shafts 344 and 346 pivoted in brackets 348 and 350. The shafts 344 and 346 carry downwardly extending arms 35I and 352 which are connected to the piston rods I22 and I20 respectively.

The operation of the machine disclosed will be cam 330 breaks the toggle 332 and thereafterthe collar 3I8 abuts the extension 3, forcing the slide :06 to the right and'removing the finished r work piece in the recess 3I0 from the position in front of the tool slide 286. If now the rod 54 be returned leftwardly to center position the cam 332 will engage the center pin of the toggle 320,

forcing the same upwardly and causing the slide 304 to be moved to'the left. A fresh work piece which was previously positioned in the recess 308 is thus presentedin front of the tool slide 284.

The work piece may beclamped by moving the piston rod I22 to the right whereupon the apparatus is ready to perform a broaching stroke by moving the slide 284 downwardly. I

It will be noted that on the leftward movement of the piston rod 54 the under surface of the cam 332 will engage the center pin of the toggle 320, forcing the same downwardly a slight amount against the spring 336. As soon as the cam 32 passes the toggle pin the latter moves upwardly again under. the urge of spring 336 so that the pin will again lie in the path of the upper surface of the cam 332 on its leftward movement. Atthe completion of the broaching stroke of the slide 294, the slide 286 is returned to its upper position and a similar cycle may be repeated except that the rod 54 moves to the left and returns to center pushing the slide 304 back to the left and returning the tool slide 286. Thereafter the clamp 342 may be operated and a broaching cycle performed at the slide 286.

'In operation of the hydraulic transmission sys-' tem, starting with the parts in the position shown in the drawing, in which the right hand broaching piston I6 has :just completed a broaching stroke and the left hand piston I4 just com-. pleted a return stroke, the clamping pistons H6 and H8 are both in released position and the piston 82 is in center position having reached that position by a rightward movement during which the fixture for the right hand broach was loaded. With themotor I in operation, fluid is delivered by the pump I6 to the conduits 86, 32 and 84 and valves 96 and 38 and conduits IIOand II2 to the rod ends of cylinders I04 and I06 thus maintaining pressure thereon while excess fluid passes over the relief valve 81. pump I6 is thus available for all of the pilot circuits.

With the valves 246 and 248 in the position shown, that is the run position, the relief .valve control chambers 32 and 60 are blocked at ports P of these valves so that, unless vented through other paths, the valves 28 and 58 will close. Valve 581s at this time, however, vented through the conduit 204, ports 206 and 2I0 of valve 208, conduit 2I2, ports 2I4 and 2I8 of valve 2I6 and con-- duit 20 to tank thus permitting oil to by-pass from the pump I4 through conduit 56 and valve 68 to the tank. The main ram pistons 14 and I6 accordingly remain stationary. The other venting path for the relief valve 28 is blocked however. This path may be traced through the conduit I34, valve I36, conduit I42, ports P and I of valve I44, conduit I48, ports P and 2 of valve I50, conduit I86, ports 2 and P of valve I58, the latter of which is plugged. Pressure accordingly builds up in the conduit 26 sufficiently to open back pressure valve 34, so that pressure oil is delivered through conduit 40, valve 42 to the left hand end of cylinder 50, thus causing piston 52 to move to the right for unloading the finished work piece from the right hand side of the machine. Oil discharged from the right hand end of cylinder 50 returns through conduit 46, valve 42 and conduit 44 to the tank. As soon as the piston 52 has started this'movement, cam I40 rides off, plunger I38 closes the valve I36 and thus insures that the vent path for the relief valve 28 remains blocked thereafter. 7 As the piston 52 reaches the end of its rightward stroke, trip 258 actuates forked lever 256 clockwise, shifting the valves I24 and I44 to reverse their connections. The valve 42 is accordingly shifted by pilot pressure transmitted through conduit I26, ports P and 2 of valve I 24 and conduit I32 to the right hand operating chamber of valve 42. Fluid returns from the left hand chamber through conduit I30, ports I and T of valve I24 and conduit I28 to the tank. I Pres- Fluid, supplied by the sure oil from the pump I2 accordingly is admitted to conduit 46 and the right hand end of cylinder 50 causing the same to move to the left for the purpose of loading the left side of the machine.

Just before piston 52 reaches its central position, latch trip 268 shifts star wheel 266 and valve I90 to establish a pilot circuit for operation of the valve 98. This circuit is from conduit 92 through conduit I92, ports P and I of valve I90, conduit I96, ports 2 and 1? of valve 200 and conduit 202 to the operating chamber of valve 98. The latter accordingly shifts to the left against its spring bias admitting pressure oil from the conduit 94 to the conduit II4 causing the piston II8 to move to the right for clamping the work in the left hand side of the machine.

As the piston 52 reached central position the cam I depressed the plunger I38 of valve I36 opening communication from the control chamber 32 of valve 28, through conduit I34, valve I36, conduit I42, ports P and 2 of valve I44 (which was previously shifted), conduit I62, ports P and 2 of valve I64, conduit I10, ports 2 and T of valve I12 and conduit I14 to tank. Valve 28, accordingly, opens thus by-passing the delivery of pump I2 at zero pressure.

As the clamping piston II8 reaches the outer limit of its stroke, the plunger of valve 208' is depressed, blocking the vent circuit for valve 58 and opening the pilot circuit for operation of valve 62. The vent conduit 204 is blocked at the ports 2062I0 of the valve 208. The pilot circuit is established from conduit 92 through the conduit 224, ports 222 and 226, and conduit 228 to the right hand operating chamber of the valve 62 thus shifting the latter to the left and admitting pressure oil from the pump I4, through conduit 56, relief valve 58 which is now closed, valve 62 and conduit 66 to the head end of cylinder 10. Piston 14 accordingly descends, forcing oil out of the rod end of cylinder 10 through the conduit 82 to the rod end of cylinder 12. Piston 16 is accordingly caused to be returned to the top simultaneously with the downward movement of the piston 14. Oil discharged from the head end of cylinder 12 returns to tank through the conduit 68, valve 62 and tank conduit 64.

As the rod 18 reaches the lower limit of its movement, latch trip 284 actuates star wheel 282 and valves I58 and 200 to reverse the connections thereof. Reversal of valve 200 relievesthe pressure from the operating chamber of valve 98 and permits the valve to return to its right hand position, discharging oil through conduit 202, ports P and I of valve 200, conduit I98, ports 2 and T of valve I90 to conduit I94 to the tank. Pressure oil from the pump I6 accordingly passes from the conduit 94 through valve 98 to the conduit H2 and the rod end of cylinder I06 thus moving piston II8 to the left for unclamping the work at the left side of the machine. As the piston II8 starts to the left the plunger of valve 208 is released thus again opening the vent circuit 204 for the relief valve 58 and at the same time cutting off port 226 from port 222 and connecting the former to the tank port 238. The valve 62 does not shift at this time, however, since a pressure connection is not yet established to the left hand operating chamber thereof. The valve 58 opens due to venting of the control chamber 60 thus by-passing the discharge of pump I4 at no pressure. The broaching pistons 14 and 16 accordingly remain stationary.

As the piston I I8 approaches the left limit of its stroke, latch trip 216 actuates star wheel 212 clockwise to reverse connections in the valve I64, connecting port P with port I and port T with port 2. The vent circuit for valve 28 is accordingly blocked by this shift since the chamber 32 is now in communication through conduit I34, valve I36, conduit I42, ports? and 2 of valve I44, conduit I62, ports P and I of valve I 64, conduit I68, port I of valve I12 with port P thereof which is blocked.

With the valve 42 remaining in its left hand position, to which it was previously moved, pressure builds up in the conduit 26 and oil passes through valve 34, conduit 40, valve 42, and conduit 46 to the right hand end of cylinder 50 causing the same to move to the left for the purpose of unloading the left side of the machine. As the piston 52 starts its movement, plunger I38 is released by cam I40 thus insuring that the vent circuit for valve 28 is maintained blocked.

As the piston 52 approaches the left limit of its stroke, trip 260 actuates the forked lever 256 clockwise thus shifting valves I24 and I44 to the position shown in the drawings. Valve I 24 establishes a pressure connection through conduit I26, ports P and I of valve I 24 and conduit I30 to the left end of valve 42 thus shifting the same to the right and reversing pressure and tank connections to the cylinder 50. Piston 52 accordingly returns to the right toward center position and as the latter is reached, cam I40 depresses plunger I48 thus opening a vent connection for the valve 28, which connection is made by'the new position of valve I44. This circuit is from the control chamber 32 through conduit I34, valve I36, conduit I42, ports P and I of valve I44, conduit I48, ports P and 2 of valve I50, conduit I56, ports 2 and T of valve I58 and conduit I60 to the tank. Relief valve 28 accordingly opens, by-passing the delivery of pump I2 and stopping the piston 52 in its central position.

As the piston 52 approached central position, moving to the right, latch trip 264 actuated the star wheel 262 counterclockwise, shifting valve I16 to establish a pilot circuit for actuating the valve 96. This circuit is from the pressure conduit 92, through conduit I18, ports P and 2 of valve I16, conduit I84, ports I and P of valve I86 and conduit I88, to the actuating chamber of valve I96. The latter shifts to the left against its spring bias connecting pressure oil delivered from the pump I6 through the conduits 86 and 92, valve 96, and conduit I08, to the head end of cylinder I04. Piston I I6 accordingly moves to the left to clamp-the work in the right side of the machine.

As the piston II6 approaches the end of the stroke, rod I20 depresses the plunger of valve 2I6, blocking the vent for relief valve 58 at the ports 2I4 and 2I8 and establishing a pressure connection through conduit 232, port 230, port 234 and conduit 236, to the left hand operating chamber of the valve 62, shifting the same to the right. Relief valve 58 closes causing oil pressure to build up in conduit 56 which is transmitted through the valve 62 and conduit 68 to the head end of cylinder 12 forcing the piston 16 downwardly. The piston 14 ascends simultaneously, discharging oil from the head end of cylinder 10 through conduit 66, valve 62 and conduit 64 to the tank. The work piece at the right hand side of the machine is accordingly broached while the left hand side of the machine performs its return stroke. When rod 80 approaches its lowermost position trip 280 actuatesstar wheel 218 counterclockwise, shifting valves I86 and I12.

' been described is accordingly repeated. There strokes to respectively load and unload work The valve 96 is accordingly permitted to return to the right under its spring bias, discharging oil through conduit I88, ports P and 2 of valve I86, conduit I82, ports I and T of valve IIIiv and conduit I80 to the tank. Pressure oil from the pump I6 is accordingly admitted through conduit 92, valve 06 and conduit IIO to the rod end of cylinder I04, unclamping the work at the right side of the machine. ,At the beginning of this stroke, the plunger of valve 2I6 is released thus again opening the vent circuit for relief valve 58 through conduit 204, ports 206 and 2I0 of valve 208, conduit 2I2, ports 2I4 and 2I8 and valve 2I6 and conduits 220 and. 244 to tank. Relief valve 58 accordingly opens, by-passing the discharge of pump I4 and permittingthe broaching pistons to remain stationary in theposition illustrated.

As the end of the stroke of piston H6 is reached, latch trip 214 actuates star wheel 210 counterclockwise, shifting the valve I50 and again blocking the vent circuit for relief valve 28. This circuit is now from chamber 32, through conduit I34, valve I38, conduit I42, ports P and I of valve I44, conduit I48, ports P and I of valve I50, conduit I54, and. port I of valve I58 to the port P which is plugged.

The same cycle of operations which has just is a difference in the second cycle, however, iii that all of the star wheel operated'valves are oppositely connected at any phase of the cycle 'to the connection which existed during the first cycle. At the end of the second complete cycle the third cycle repeats with the star wheel valves going through the same sequence as occurred in the first cycle. a

When it is desired to stop the continuous operation of the machine, the valves 240 and 248 may be shifted to connect port I with port T of each, thus venting both the relief valves 28 and 58 through the conduits254 and 252 respectively. When this is done, the discharge of both pumps I2 and I4 is by-passed and the machine willstop at any point in the cycle, except during a clamping or unclamping sequence.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A hydraulic power transmission system for operating a dual ram broach having a pair of poweroperated broach slides, a power operated loading and unloading device operable on two separate forward strokes to respectively load a work piece at'one slide and unload a work piece at the other slide, and on two separate reverse strokes to respectively load and unload work pieces at the opposite slides, and power operated clamping means at each slide, comprising in combination, pumping means, a broaching motor, a pair oi! clamping motors and a loading and unloading motor, means for controlling the supply oi fluid to said motors, and an operating system for said control means to provide a continuous cycle or loading, clamping, broaching, unclamping and unloading at each slide alternately.

2. A hydraulic power transmission system for operating a dual. ram broach having a pair of power operatedbroach slides, a power, operated at the other slide, and on two separate reverse pieces at the opposite slides, and power operated clamping means at each slide, comprising in combination, pumping means, a broaching motor, a pair of clamping motors and a loading and unloading motor, meansfor controlling the supply of fluid to said motors, and an operating system for said control means to provide a continuous cycle of loading, clamping, broaching unclamping and unloading at each slide alternately, said operating system including interlocking means for initiating operation of each motor only when the other motors have completed their intended operations.

3. A hydraulic power transmission system for operating a dual ram broach having a pair of power operated broach slides, a power operated loading and unloading device operable on two separate forward strokes to respectively load a work piece at one slide and unload a work piece at the other slide, and on two separate reverse strokes to respectively load and unload work pieces at the opposite slides, and power operated clamping means at each slide, comprising in combination, pumping means, a broaching motor, a pair of clamping motors and a loading and unloading motor, means for controlling the supply of fluid to said motors, and an operating system for said control means to provide a continuous cycle of loading, clamping, broaching, unclamping and unloading at each slide alternately, said operating system including means for initiating operation of the loading motor in response to operation of both a clamping motor and the broaching motor.

4. A hydraulic power transmission system for operating a dual ram broach having a pair of 'power operated broach slides, a power operated of loading, clamping, broaching, unclamping and unloading at each slide alternately, said operating system including means for initiating operation of the loading motor in response to operation of both a clamping motor and the broaching motor, and means for alternately controlling the loading motor flrst from one clamping motor and then from the other. l

5. A hydraulic power transmission system for operating a dual rambroach having a pair of power operated broach slides, a power operated loading and unloading device operable on two separate forward strokes .to respectively load a work piece at one slide and unload a work piece at thev other slide, and on two separate reverse strokes to respectively load and unload work.

pieces at the opposite slides, and power operated clamping means ateach slide, comprising in combination, pumping means, a broaching motor, a pair of clamping motors and a loading and unloading motor, means for controlling the supply of fluid to said motors, and an operating system for said control means to provide a continuous cycle of loading, clamping, broaching, unclamping and unloading at each slide alternately, said operating system including means for initiating operation of clamping motor in response to operation of both the broaching motor and the loading motor.

6. A hydraulic power transmission system for operating a dual ram broach having a pair of power operated broach slides, a power operated loading and unloading device operable on two separate forward strokes to respectively load a work piece at one slide and unload a work piece at the other slide, and on two separate reverse strokes to respectively load and unload work pieces at the opposite slides, and power operated clamping means at each slide, comprising in combination, pumping means, a broaching motor, a pair of clamping motors and a loading and unloading motor, means for controlling the supply of fluid to said motors, and an operating system for said control means to provide a continuous cycle oi loading, clamping, broaching, unclamping and unloading at each slide alternately, said operating system including means for initiating operation of each clamping motor in response to respectively opposite operations of both the broaching motorand the loading motor.

7. A hydraulic power transmission system for operating a dual ram broach having a pair of power operated broach slides, 'a power operated loading and unloading device operable on two separate forward strokes to respectively load a work piece at one slide and unload a work piece at the other slide, and on two separate reverse strokes to respectively load and unload work pieces at the opposite slides, and power operated clamping means at each slide, comprising in combination, pumping means, a broaching motor, a pair of clamping motors and a loading and unloading motor, means for controlling the supply of fluid to said motors, and an operating system for said control means to provide a continuous cycle of loading, clamping, broaching, unclamping and unloading at each slide alternately, said operating system including means for initiating operation of the broaching motor in response to operation of each clamping cylinder.-

8. A hydraulic power transmission system for operating a dual ram broach having a pair of power operated broach slides, a power operated loading and unloading device operable on two separate forward strokes to respectively load a work piece at one slide and unload a work piece at the other slide, and on two separate reverse strokes to respectively load and unload work pieces at the opposite slides, and power operated clamping means at each slide, comprising in combination, pumping means, a broaching motor, a pair of clamping motors and a loading and unloading motor, means for controlling the supply of fluid to said motors, and an operating system for said control means to provide a continuous cycle of loading, clamping, broaching, unclamping and unloading at each slide alternately, said operating system including means for initiating operation of the broaching motor in opposite directions in response to operation of each clamping cylinder alternately.

9. A hydraulic power transmission system for operating a dual ram broach having a pair of power operated broach slides, a power operated loading and unloading device operable to respectively load a work piece at one slide and unload a work piece at the other slide, and to respectively load and unload work pieces at the opposite slides, and power operated clamping means at each slide, comprising in combination,

pumping means, a broaching motor, a pair of clamping motors and a loading and unloading motor, means for controlling the supply of fluid to said motors, and an operating system for said control means to provide a continuous cycle of loading, clamping, broaching, unclamping and unloading at each slide alternately, said opoperating system including means for initiating operation of clamping motor in response to operation of both the broaching motor and the loading motor.

10. A hydraulic power transmission system for operating a dual ram broach having a pair of power operated broach slides, a power operated loading and unloading device operable to respectively load a work piece' at one slide and unload a Work piece at the other slide, and to respectively load and unload work pieces at the opposite slides, and power operated clamping means at each slide, comprising in combination, pumping means, a broaching motor, a pair of clamping motors and a loading and unloading motor, means for controlling the supply of fluid to said motors, and an operating system for said controlmeans to provide a continuous cycle of loading, clamping, broaching, unclamping and unloading at each slide alternately, said operating system including means for initiating operation of each clamping motor in response to respectively opposite operations of both the broaching motor and the loading motor.

11. A hydraulic power transmission system for operating a dual ram broach having a pair of power operated broach slides, a power operated loading and unloading device operable to respectively load a work piece at one slide and unload a work piece at the other slide, and to respectively load and unload work pieces at the opposite slides, and power operated clamping means at each slide, comprising in combination, pumping means, a broaching motor, a pair of clamping motors and a loading and unloading motor, means for controlling the supply of fluid to said motors, and an operating system for said control means to provide a continuous cycle of loading, clamping, broaching, unclamping and unloading at each slide alternately, said operating system including means for initiating operation of the broaching motor in response to operation of each clamping cylinder.

12. A hydraulic power transmission system for operating a dual ram broach having a pair of power operated broach slides, a power operated loading and unloading device operable to respectively load a work piece at one slide and unload a work piece at the other slide, and to respectively load and unload work pieces at the opposite slides, and power operated clamping means at each slide, comprising in combination, pumping means, a broaching motor, a pair of clamping motors and a loading and unloading motor, means for controlling the supply of fluid to said motors, and an operating system for said control means to provide a continuous cycle of loading, clamping, broaching, unclamping and unloading at each slide alternately, said operating system including means for initiating operation of the broaching motor in opposite directions in response to operation of each clamping cylinder alternate- 13. A duplex hydraulic broaching machine comprising a pair of alternately operative and oppositely moving broaching slides, a separate work support for each broaching slide, means to move said work supports simultaneously and and clamping devices secured to the fixed frame of the machine and operative to engage and clamp a piece of work-on a work support only after said support and Work. have been fully moved to breaching position.

14. A duplex hydraulic broaching machine comprising a pair of alternately operative and oppositely moving broaching slides, a separate 10 work support for each broaching slide, means to move said work supports simultaneously and oppositely to loading and broaching positions, devices to clamp the work on a work support only after said support and work have been fully moved to broaching position, and control devices operatively interlocking said work support and. said clamping devices and automatically preventing movement of said work supports so long as either clamping device is operative.

HUGH C. NYE. 

